A transformer
converts direct current into alternating current
converts alternating current into direct current
steps up or steps down a given alternating current voltage
supplies current with zero resistance
Correct Answer :
C. steps up or steps down a given alternating current voltage
Related Questions
The best estimates of the age of the earth comes from the studies of
angle of inclination of the earth
changes in radio-active minerals in it
period taken by Sun's light to reach the earth
artificial satellites revolving round the earth
The electroplating of a metallic article
protects the article from atmospheric corrosion
gives it a more attractive appearance
Both (a) and (b) above
None of the above
If you want a sound proof room, the walls should be
able to refract the sound
good absorbers of sound
good reflectors of sound
All the above
When a body Is taken to the poles from the equator, Its weight becomes
greater
less
the same
None of these
When a particle in motion is acted upon by a force in a direction perpendicular to the direction of motion, the path followed by the particle will be
a straight line
an ellipse
a circle
a parabola
Lightning is produced when
similar charges of electricity rush towards each other and then get repelled
clouds strike against impurities in air and the friction burns up these impurities
strong opposite charges in different clouds break down the resistance offered by the intervening air
water vapour produces electricity in the clouds
The speed of sound in air at 0° C is approximately
4 x 10 8 m/s
1500 m/s
330 m/s
500 m/s
Which force is used when milk is churned to separate cream?
cohesive
centrifugal
frictional
gravitational
When ice just melts
there is no change in volume
there is no change in temperature
heat is given out
there is no change of state
The asteroids belt lies between the orbits of
Earth and Mars
Venus and Earth
Mars and Jupiter
Moon and Mars
An electric charge is measured in
coulomb
ampere
volt
watt
Sound travels fastest in
air
water
iron
vacuum
Besides protons, the nucleus of an atom contains
electrons
neutrons
neutrons and electrons
electrons, neutrons and other particles
The device that is used to measure the electromotive force of a cell is
an ammeter
a rheostat
a voltmeter
a voltameter
The mass number and the atomic number of an element are X and Y respectively. The number oC neutrons in the atom of that element is
X
Y
X + Y
X Y
A proton is
a quantum of light energy
a quantum of matter
a positively charged atomic particle
another name for positron
Nuclear fission process means
absorption of a neutron by a nucleus
breakup of the nucleus of a heavy atom into two nearly equal halves emitting two or three neutrons and releasing large amounts of nuclear energy in the process
the scattering of neutrons
formation of heavier nucleus
The velocity of sound in a medium is
directly proportional to its pressure
inversely proportional to the square root of its pressure
directly proportional to the square root of its pressure
independent of its pressure
To produce beats it is necessary to have two waves
travelling in opposite direction
of slightly different frequencies
of equal wavelength
of equal amplitude
A hydrogen bomb is based on
nuclear fusion
nuclear fission
Both (a) and (b) above
Neither (a) nor (b)
An electric kettle used for boiling hard water has a white scale deposited on its heating element. This consists or
sugar
sodium carbonate
common salt
carbonates of calcium and magnesium
The asteroids belt lies between the orbits of
Earth and Mars
Venus and Earth
Mars and Jupiter
Moon and Mars
Electromagnets are used in
the telephone ear piece
the telegraph
the electric bell
All the above
The inside of both the walls of a thermos flask is silvered i.e., on the vacuum side in order to reduce heat loss by
convection
radiation
conduction
All the three
The planet that spins Caster than any other planet is
Saturn
Jupiter
Earth
Mercury
Sound waves in air are
transverse
longitudinal
transverse and longitudinal
neither transverse nor longitudinal
Warm air will hold more water vapour than cold air because
it is lighter
it has more water vapour in it
its molecules are close together
its molecules are far apart
A piece of cork la embedded inside an ice block which floats in water. What will happen to the level of water when all ice melts?
It will go down
It will come up
It will remain at the same level
First it will go down and it will come up
A proton is
the ionised hydrogen molecule
the nucleus of helium atom
the nucleus of hydrogen atom
the positive counterpart of electron
Pyrometers are instruments used
for measuring the velocity of wind
in the manufacture of fireworks
in finding the coefficient of apparent expansion of a liquid
for measuring high temperatures